2 Replies Latest reply on Dec 31, 2015 7:58 AM by Finn Carlsvi

    Propeller wash does not seem accurate

    Finn Carlsvi

      Hello,

      I'm trying to run a simulation of a propeller (in static condition) with duct in Solidworks 2015 Flow Simulation. The propeller diameter is 300mm and uses a clark y airfoil, it is running at 7000 rpm.

       

      The problems I am having are:

      1. The propeller wash diverges, it should converge.
      2. The propeller wash dissipates almost immediately.
      3. Propeller thrust is higher in the free case than with a duct. From what I understand, theory states that edge effects would be detrimental to the thrust of the free propeller.

       

      I've tried:

      - Increasing the domain size

      - Running the finest fidelity mesh setting

      - Changing the size of the rotating domain

      - Adding a small (0.1 m/s) global velocity component in Y (down in the diagram)

       

      Thanks for any help you can provide, I have included a zip file with the parts and how they were setup for flow simulation.

       

      / Finn

       

      Ducted propeller setup:

      cut_plot_duct.PNG

      data_duct.PNG

       

      Non-ducted propeller setup:

      cut_plot_prop.PNG

      data_prop.PNG

        • Re: Propeller wash does not seem accurate
          Amit Katz

          I played around with your model a little. Without knowing what the wash is supposed to look like (i.e. having photos from a smoke test or something) it's difficult to know if your model is accurate or not. What I did notice, however, is that one of the problems with your results is that the simulation ends too soon. It's true that your goals have converged, but since none of your goals involve the wake, it does not have enough time to fully develop. For example, I forced the ducted simulation to continue until 14 travels, and this is what I see:

          propwash2.PNG

          propwash1.PNG

           

          It's likely that this wake is still being developed. What I recommend is setting some convergence surface goals downstream of your prop. The distance is up to you, it depends on how much of the wake is important for you to study.